The invention relates to the field of gliding sports and, more particularly, to that of snowboarding. It relates more specifically to an interface element fitted between the sole of the boot and the binding (or the snowboard) to fill the gap between the sole and the binding or the board. Such interface elements are commonly known in snowboarding by the name of xe2x80x9cgas pedalxe2x80x9d.
In the remainder of the description, the invention is described in its application to snowboarding, but it could be carried over to any kind of gliding board such as for alpine skiing, cross-country skiing or the like.
As is known, snowboarding is done either with rigid boots that resemble alpine ski boots or with flexible boots that collaborate with bindings that have rigid elements, particularly a highback, intended to provide support for the flexible boot.
The invention relates more precisely to this family of flexible boots and appropriate bindings.
Such boots are actually used for their comfort, allowing the user to walk unimpeded when he has stepped out of his board.
Now, to allow the foot to roll correctly during the walking motion, flexible boots have a sole which has a slight curvature such that the front and rear ends are slightly raised.
It can thus be appreciated that, at the front and/or rear ends of the boot, when the latter is in place in the binding, there is a certain unoccupied volume between the underside of the sole of the boot and the top side of the base of the binding, or alternatively the gliding board proper, depending on the architecture of the binding used.
This volume which is free of material therefore does not allow the user to transmit loads at the front and/or rear ends of the foot, even though, as is known, these constitute one of the main zones for the transmission of thrust.
It is to be noted that this problem of effectively transmitting thrust arises to a greater extent at the front end of the boot because thrust at the rear end of the boot is transmitted mainly via the highback of the binding. Nonetheless, the absence of effective support at the rear of the heel of the boot leads to inaccuracies in the feel and therefore in the control of the board.
Some solutions have already been proposed for solving this problem.
Document U.S. Pat. No. 5,503,900 describes a binding the base of which comprises additional elements located at the front and rear ends. These elements form inclined wedges, the top side of which is intended to come into contact with the sole of the boot at the front and at the rear. Thus, loads exerted near the tip of the boot are transmitted toward the base via this wedge-forming element. The clearance between the sole of the boot and the top side of the base is eliminated, which allows loads to be transmitted right from the first movements of the tip of the foot. The major drawback with these wedge-forming elements is that they are not able to adapt to suit different boot sizes, and that they therefore have to be repositioned each time the user changes boots.
Another source, document WO 98/42,419 proposes that the wedges be made adjustable in terms of longitudinal and transverse position, so that they can be adapted to suit different sole configurations. However, as the element has a given shape, it cannot correspond to all shapes of boot soles on the market.
Such a solution therefore has the major drawback that the wedge-forming element is present on only part of the surface of the sole of the boot, which means that the bearing surface of the boot is not used to the full and that some of the loads exerted by the user is not put to good use.
Furthermore, it is found that according to the various boot sole curvatures, a certain clearance may arise between the sole and the wedge-forming element. This clearance produces the aforementioned detrimental effects.
Finally, a certain amount of slippage may arise between the top face of the wedge-forming element and the sole, thus limiting the effectiveness with which loads are transmitted.
One of the problems that the invention sets out to solve is therefore that of optimizing the contact between the wedge-forming interface element and the sole of the boot in order to obtain the best possible transmission of loads.
The invention therefore sets out to provide an interface element intended to be inserted between the sole of the boot and the binding or the top side of the board, which affords optimum support irrespective of the size of the boot and of its geometry.
The invention therefore relates to an interface element used on a gliding board, said element being inserted between the sole of the user""s boot and the top side of the board so as to transmit the thrust exerted toward the board by the user at least at the front end of the sole.
The element according to the invention is one which comprises at least one zone made of a thermoformable material capable, after exposure to heat, of matching the imprint of at least the front end of the sole of the boot so as to fill the volume between the top side of the board and the sole of the boot.
In other words, the characteristic element is made of a material which can adopt the exact shape of the underside of the sole of the boot, which allows the boot to be immobilized extremely precisely in position with respect to the binding.
The collaboration between the patterns on the sole and the corresponding patterns molded in the thermoformable zone provides almost perfect immobilization of the boot with respect to the binding, regardless of the sole geometry.
Furthermore, the thermoformable material used is compressed and therefore rigidified at the time of molding by the sole, which increases its ability to transmit thrust, particularly by comparison with the devices of the prior art made of elastomeric materials.
The interface element according to the invention can be fitted either directly over the base of the binding or directly over the top side of the board when the architecture of the binding has no base, such as in bindings of the type known by the designation xe2x80x9cbaselessxe2x80x9d.
The interface element may equally be placed directly on the top side of the board and pass through the base of the binding in openings made therein for that purpose.
The interface element according to the invention may be present either at the front end of the boot or at the rear end of the latter, or at both these ends. It may alternatively form a single element covering the entire surface of the sole of the boot, extending from one end of the latter to the other.
In an advantageous form, the interface element comprises, at the front and/or rear ends, and beneath the zone of thermoformable material, an additional zone of rigid material so as to provide for good transmission of thrust exerted toward the board.
In effect, according to this characteristic, the rigidity of the interface element, at the front or rear ends, is relatively great and combines the rigidity of the thermoformable zone proper with that of the underlying zone.
When the interface element extends under the entire length of the boot, it may prove advantageous for it to comprise at least in the region of the heel and beneath or at the location of the zone of deformable material, a zone of flexible material so as to damp vibrations from the board, and to damp jolts, particularly when taking jumps.
In other words, at its rear end the interface element has a relatively compressible zone which absorbs some of the energy of the vibrations transmitted by the board, in the region of the sole where the transmission of thrust is not predominant.
Advantageously in practice, the interface element according to the invention may be covered with an impervious protective layer made, for example, of a fabric coated with polytetrafluoroethylene. Such a protective layer prevents snow, water and ice from getting into the cells of the foam of the thermoformable element. Such a protective layer may also bear decoration.